Discussion in 'Panasonic Cameras' started by Trigger, Jun 13, 2013.
In the WB menu on my G3, I see a Kelvin setting; what is that supposed to be set at?
My guess would be color warmth/coolness as Kelvin is a temperature scale used by scientists. Only a guess tho.
Yes, I know what it does, just wondering where it should be set.
Yeah, scientists ... and photographers in an attempt to characterize the emitted spectrum of various kinds of lights. Google is your friend or just use about white balance (WB) until you figure out a better way to use WB or color temperature settings.
Different lights have different distributions of energy across the wavelength spectrum and color temperature is a way to try to explain that distribution. Comes from black body radiation courtesy of Einstein and statistical mechanics using quantum mechanics and classical thermodynamics blended together in one is the earliest cases.
Depends on the lights that are around ...
Color temperature - Wikipedia, the free encyclopedia
So according to that chart on Wiki, for daylight shooting, one should have the camera set at about 6500? ...Or does the camera change the Kelvin when you change the specific WB?
In the context photography WB and Kelvin temperature are just two different ways of saying the same thing. WB is a process and Kelvin is a measure of color. One needs to know the color of the light to perform the correct white balance.
Some cameras/SW just have "daylight" while others have Kelvin and tint. Color temperature is never enough to do accurate WB and tint helps but as a general solution to complex lighting even WB, Kelvin and tint are not up to the task but generally close enough.
It's just that I found the Kelvin setting on my camera at 2500, while in Auto WB. Is that correct, or should it be at good ol' 6500?
Auto WB lets the camera decide which color temperature to use. As you can imagine it does not always get it right! Also auto WB will change with every shot. If you find your colors are not unreasonable then auto WB is likely doing a decent job of it so leave it. If you are a control freak, like me, then print up a "cheat sheet" and set WB explicitly as needed.
You can have it both ways and let the camera use auto WB (which only applies to jpeg) and shoot jpeg+raw and adjust your WB in post processing to make your raw into a new jpeg. Adjusting WB on a jpeg (in post) is possible but can be tricky sometimes.
Sounds good. (I shoot Raw only). But I'm still wondering why the setting is at 2500; does it just go down there as a default when in Auto WB, and then gets changed when an image is taken, based on the lighting conditions?
Who knows how the various camera manf come up with their auto functions? Pretty much has to be based on image content.
I believe that if you're shooting RAW, you can change the White Balance in post processing to your preferred choice so your in-camera selection will only affect the preview jpeg.
Ok, so if shooting in Raw, the Kelvin setting doesn't matter, is that correct?
The lower the number, the warmer the overall tone of the photo will be. "Warmer" = reddish content.
As you increase the number, we add a bluish look. Visually, imagine a wire that is "red hot", which is approximately 2500 degrees. If we continue increasing the physical temperature, eventually it turns "white hot".
The degrees kelvin adjustment provides the means for manually adjusting the color temperature to a specific value. The "right" setting is one that matches the illumination you are using. The best method is to get yourself a white reference card. Manually white balance your camera to the white card, illuminated by the light you are shooting in. Auto WB can be fooled if you are shooting under lighting that is something other than white.
You got those flipped. Warmer is orange, colder is blue. Personally, I just use CWB with a grey card when I don't use AWB.
Kelvin is Celsius + 273 degrees, so if you were going to set it at 6500C, you would set it at 6227K, but that doesn't tell you about your setting because I don't know if that setting is supposed to be C or K.
So, someone who knows that the difference between Kelvin and Celsius is that Celsius is referenced (0º) to the freezing point of distilled water, and Kelvin is referenced to absolute 0 (all atomic motion stops), but doesn't know that color temperature is only referenced to the Kelvin scale.
The only use I've found for setting WB to a Kelvin temp, is when using a light source with a stable, fixed color temp. "Sunlight" is only a nominal temp, because it can vary due to atmospheric conditions.
The color temperature of the electromagnetic radiation emitted from an ideal black body is defined as its surface temperature in kelvins, or alternatively in mired (micro-reciprocal kelvins). This permits the definition of a standard by which light sources are compared - As the day progresses, colour temperature changes for daylight between sunrise & sunset, then there are also differing colour temperatures for different indoor light sources (tungsten/floursescent etc)
The Sun closely approximates a black body radiator. The effective temperature, defined by the total radiative power per square unit, is about 5,780 K. The color temperature of sunlight above the atmosphere is about 5,900 K.
As the Sun crosses the sky, it may appear to be red, orange, yellow or white depending on its position. The changing color of the sun over the course of the day is mainly a result of scattering of light, and is not due to changes in black body radiation. The blue color of the sky is caused by Rayleigh scattering of the sunlight from the atmosphere, which tends to scatter blue light more than red light.
Daylight has a spectrum similar to that of a black body with a correlated color temperature of 6,500 K (D65 viewing standard) or 5,500 K (daylight-balanced photographic film standard).
In digital photography, color temperature is sometimes used interchangeably with white balance, which allow a remapping of color values to simulate variations in ambient color temperature. Most digital cameras and RAW image software provide presets simulating specific ambient values (e.g., sunny, cloudy, tungsten, etc.) while others allow explicit entry of white balance values in kelvins. These settings vary color values along the blue–yellow axis, while some software includes additional controls (sometimes labeled tint) adding the magenta–green axis, and are to some extent arbitrary and subject to artistic interpretation.
See Industry scale below that shows varying temperatures:
I personally hate the use of Kelvins to describe color or color cast. From my own experience, Kelvin really only deals with the amount of Blue, or lack of blue.
What this means is that for example, I can by two 10,000k Flourescent bulbs( fish tank, for example ) and one bulb be more purplish magenta while the other have more a greenish cast. This trend is even worse as K increases, say 14000K or 20000K. Why are they labeled the same? Because they emit the same amount of blue.
FilelanckianLocus.png - Wikipedia, the free encyclopedia
If we take a look at this graph, its apparent that 1500K can be more yellow orange or could be more red. The amount of blue is similar.
I'm not sure why we would use Kelvin to describe white balance. I guess this is how it has always been. Most things we photograph are not emitting light. They are reflecting light( or absorbing ). For me, in RAW, I generally don't fix WB problems using the white balance tools. I generally fix them using RGB offsets or Hue/saturation sliders. It just makes more sense to me.
I am with you on this one and used to hate using kelvin meters when we had to photograph items for investigation / documentation purposes, indoors as you indicate, two lights the same could have differing temepratures due to usage and then the consideration of ambient lighting as well then having to use the correct colour correction filter to render the negative with the right colour balance ...........it was a pain!
We are spoilt today with digital cameras being as flexible as they are and that fact coupled with good software packages, setting correct colour balance on the camera is not as critical as it used to be.............thank goodness.
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